Below are easy install instructions by OS and Architecture. As always there are always the standard instructions in the README.md as well.
linux
amd64 - linux
# Export the sha256sum for verification.
$ export RIDDLER_SHA256="cf319c1be2f6007736c6a618d0746dcff4f291fc112c9d7150c5270b4c182580"
# Download and check the sha256sum.
$ curl -fSL "https://github.com/genuinetools/riddler/releases/download/v0.6.3/riddler-linux-amd64" -o "/usr/local/bin/riddler" \
&& echo "${RIDDLER_SHA256} /usr/local/bin/riddler" | sha256sum -c - \
&& chmod a+x "/usr/local/bin/riddler"
$ echo "riddler installed!"
# Run it!
$ riddler -h